Tilting pad thrust bearing arrangements are well known per se, having discrete bearing pads and against which the pads bear to transmit axial thrust forces.
The supporting carrier means is formed either as a metal ring of such thickness as to support the thrust loads without deformation or sometimes as a prepared surface of the apparatus housing the bearing arrangement. In either case it is conventional for the pad-supporting face of the carrier means to be substantially flat in the axial direction, except possibly for lubricant nozzles at the surface, and for the face of each thrust pad opposite to a bearing surface to be machined away except at a central or circumferentially off set location to leave a radially-extending fulcrum ridge by way of which the pad is supported on said supporting face of the carrier means and about which fulcrum ridge it is able to make limited tilting movement.
It will be appreciated that in the case of individual pads or an integral ring of such pads, the provision of such fulcrum ridge on the supported pad surfaces involves an additional and nontrivial manufacturing stage.
GB-A-1535165 describes a thrust bearing arrangement wherein parallel surfaced bearing pads are supported on a smooth faced carrier by way of an intervening plate machined such that it presents an upstanding fulcrum ridge to each bearing pad. Whereas this construction permits the bearing pads to be of simpler and cheaper construction, the machined plate nevertheless requires considerable manufacturing effort.
GB2308162 describes an alternative arrangement wherein, and having regard to FIGS. 1 and 2 hereof, the bearing assembly 400 comprises an annular body 106 which carries an array of bearing pads 402, either as discrete pads or in an integral ring of pads separated by webs of pad material. The pads are manufactured with opposite faces flat and the fulcrum ridges are provided at 415 by a shim member 412 in the form of a thin circular disc of material in which a series of cuts are made to allow for a plurality of tabs 416 thus defined to be folded back on themselves about generally radial fold lines. In this manner are a plurality (usually 6, 8, or possibly 10) of fulcrum ridges defined in the regions of the shim member which are now of double thickness. It is on these that the bearing pads are loosely held in place such that they are capable of tilting when the bearing is assembled. To complete the assembly, the shim member, having the fulcrum ridges formed therein and having immediately adjacent “letter box” apertures resulting from the folding of the shim material on top of itself, is disposed between the pads and a correspondingly flat surface of the body 106. By such means may the bearing pads be manufactured without any expensive additional machining to define fulcrum ridges integrally thereon, and additionally, the provision of a shim member in which a discrete number of folds have been effected further allows for cost reduction, again because there is no requirement for machining of the shim member.
Notwithstanding the above, there is still requirement for the each and every shim member to be worked, and therefore the cost reduction by minimizing work for individual pads is effectively negated.
It is an object of this invention to provide a tilting pad thrust bearing which minimizes both machining and working on all of the components in the bearing, and thus concomitantly provides a bearing of minimal cost.